Zakuani had been a doubt for the televised clash on Saturday evening after a dead leg forced the key central defender off during last weekend's defeat at Derby, which left Posh hovering precariously just above the relegation zone on goal difference.
Right wing-back Mark Little and centre-half Michael Bostwick could come back into the reckoning, despite both players having been previously ruled out for the season with hamstring injuries.
Posh boss Darren Ferguson said: "Gaby should be fit now and Mark and Michael have both been making good progress. Mark has been responding well to treatment and will join in training on Thursday.
"Michael has been running and he's been doing well, but I would say he has less chance of playing than Mark."
Peterborough could find themselves in the drop zone by the time they kick-off at 5.20pm, depending on results involving Barnsley and Wolves.
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- Michael Bostwick